Basically substituted indole derivatives

Abstract

The present invention relates to basically substituted indole derivatives and to a process for their manufacture.

The novel compounds are valuable medicaments which exhibit hypotensive and antiarrhythmic activity on the cardiac circulation system.

Description

The present invention relates to new basically substituted indole derivatives and the physiologically acceptable acid addition salts thereof, to a process for the manufacture of these compounds as well as to pharmaceutical compositions thereof.

It has been found that indole derivatives which carry basic substituents in 2- and/or 3-positions have valuable pharmacological properties, especially on the heart's circulatory system.

Hence, object of this invention are indole derivatives of the formula I ##STR1## in which:

R¹ stands for an amino group of the formula ##STR2## wherein R⁵ and R⁶ are identical or different, and each stands for an alkyl group of 1 to 6 carbon atoms or these alkyl groups together with the nitrogen atom may also form a 5- to 8-membered ring which may carry, at a carbon atom, an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, a hydroxy, carboxy or alkoxy-carbonyl group of 1 to 4 carbon atoms and in which one of the carbon atoms may be replaced by an oxygen, sulfur or nitrogen atom and the hydrogen atom of the latter may be substituted by the thienyl, furyl, pyridyl, dihydro-pyridyl or formyl group, an alkenyloxycarbonyl group of 3 to 6 carbon atoms or an alkinyloxycarbonyl group of 3 to 6 carbon atoms, an alkoxycarbonyl group of 1 to 4 carbon atoms, which may be substituted by hydroxy or alkoxy of 1 to 4 carbon atoms, the phenyl group which may carry one or more alkyl groups of 1 to 4 carbon atoms, alkoxy groups of 1 to 4 carbon atoms, methylene dioxy, hydroxy, nitro or amino groups or halogen atoms, and the hydrogen atom at the nitrogen atom may further be substituted by the radical --COR⁹, wherein R⁹ stands for hydrogen or a phenyl group, optionally having the substituents as mentioned above, or by an alkyl group of 1 to 4 carbon atoms which may be substituted by hydroxy, alkoxy of 1 to 4 carbon atoms, dialkylamino of 1 to 4 carbon atoms, ethylene-dioxy, trimethylene-dioxy or phenyl which may be substituted as mentioned above or by an aminocarbonyl group of the formula ##STR3## wherein R⁷ and R⁸ have the same meanings as R⁵ and R⁶, with the proviso that together with the nitrogen atom they may form an unsubstituted heterocyclic ring containing only one hetero atom,

R² stands for a hydrogen atom, a saturated or unsaturated, straight-chained or branched aliphatic hydrocarbon radical of 1 to 6 carbon atoms, a phenyl group which may carry one or more alkyl groups of 1 to 4 carbon atoms, alkoxy groups of 1 to 4 carbon atoms, methylene-dioxy, hydroxy, nitro or amino groups or halogen atoms, or R² stands for an amino group of the formula ##STR4## wherein R¹0 and R¹1 have the meanings of R⁵ and R⁶ mentioned for R¹, or wherein R¹0 stands for hydrogen and R¹1 for an aminoalkyl group of the formula ##STR5## wherein A¹ is a single bond or stands for a straight-chained or branched alkylene group of up to 6 carbon atoms which may be substituted by hydroxy groups, alkoxy groups of 1 to 4 carbon atoms or acyloxy groups and wherein R¹2 and R¹3 are identical or different and each stands for hydrogen, cycloalkyl of 5 to 7 carbon atoms, an alkyl group of 1 to 6 carbon atoms which may be substituted by acetoxy, alkoxy of 1 to 4 carbon atoms, acetylamino or formamino, or a phenyl group which may be substituted as mentioned above, or wherein R¹2 and R¹3 together with the nitrogen atom form a 5-, 6- or 7-membered ring which may be substituted, at one carbon atom, by alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, phenyl, hydroxy, carboxy or alkoxycarbonyl of 1 to 4 carbon atoms, and wherein one of the cyclic carbon atoms may be replaced by an oxygen, sulfur or another nitrogen atom and the hydrogen atom at this latter may be substituted as defined for the amino group of the formula ##STR6## in substituent R¹, or R¹0 may stand for hydrogen and R¹1 for alkyl of 1 to 6 carbon atoms which may be substituted by hydroxy, alkoxy of 1 to 4 carbon atoms, alkenyloxy of 3 to 5 carbon atoms, carboxy, alkoxycarbonyl of 1 to 6 carbon atoms, dialkylamino of 1 to 4 carbon atoms, cycloalkyl of 5 to 7 carbon atoms, cycloalkenyl of 5 to 7 carbon atoms, chloro, bromo, pyridyl or phenyl which may be substituted as mentioned above, or R¹1 may stand for cycloalkyl of 5 to 7 carbon atoms which may be substituted by alkyl of 1 to 4 carbon atoms, alkenyl of 2 to 4 carbon atoms, alkinyl of 2 to 4 carbon atoms or dialkylamino of 1 to 4 carbon atoms, or for the 1-adamantyl, norbornyl group or an alkenyl or alkinyl group of each 3 to 10 carbon atoms, or R² stands for an aminoalkyl group of the formula ##STR7## wherein A² stands for a straight-chained or branched alkylene group of 2 to 6 carbon atoms which may be substituted by alkyl of 1 to 4 carbon atoms or phenyl which may be substituted as mentioned above, and wherein R¹4 and R¹5 have the same meanings as mentioned for R¹2 and R¹3 ; for a basic radical of the formula --O--(CH₂)_n --R¹6, wherein R¹6 stands for a 5- or 6-membered heterocyclic ring containing a nitrogen atom, and n stands for zero or 1,

R³ stands for a hydrogen atom, an alkoxy group of 1 to 5 carbon atoms, the hydroxy group, a chlorine, bromine or fluorine atom, a nitro, amino or benzyloxy group,

m stands for an integer of 1, 2 or 3 and

R⁴ stands for a hydrogen atom, a saturated or unsaturated straight-chained or branched, aliphatic hydrocarbon radical of 1 to 6 carbon atoms, a benzyl or phenyl group, in which the phenyl groups may be substituted as mentioned above,

as well as the physiologically acceptable salts thereof.

As preferred substituents, there may be mentioned: for R¹ : the amino group of the formula ##STR8## wherein the alkyl groups R⁵ and R⁶ together with the nitrogen atom form a 5- to 8-membered ring and one of the carbon atoms may be replaced by a nitrogen or oxygen atom, especially the pyrrolidino, piperidino, hexamethylene-imino, morpholino, 4-hydroxypiperidino, 4-carbethoxy-piperidino and 1-piperazinyl group of the formula ##STR9## wherein Y stands for hydrogen, alkyl of 1 to 3 carbon atoms, phenylalkyl, wherein the alkyl-group has 1 to 3 carbon atoms, β-hydroxyethyl, 2-(1,3-dioxolan-2-yl)-ethyl, 2-(1,3-dioxan-2-yl)-ethyl, 3,4-methylene-dioxybenzyl, pyrrolidinocarbonylmethyl, phenyl or phenyl substituted by methoxy, chloro or hydroxy; allyl, 2-methallyl, propargyl, 3,4,5-trimethoxybenzoyl, 3,4-methylene-dioxybenzoyl, 2-furoyl, 2-thenoyl, alkoxycarbonyl of up to 5 carbon atoms, wherein the alkyl group of this latter may be substituted by a hydroxy group;

for R² : hydrogen, an amino group of the formula ##STR10## wherein R¹0 and R¹1 stand for identical alkyl groups of 1 to 4 carbon atoms, or together with the nitrogen atom they form a 5- to 8-membered ring which may be substituted, especially the pyrrolidino, piperidino, hexamethylene-imino, 4-hydroxy-piperidino group, and wherein one of the carbon atoms may be replaced by an oxygen or nitrogen atom, especially the morpholino and 1-piperazinyl groups of the formula ##STR11## wherein Y stands for alkyl of 1 to 3 carbon atoms, phenylalkyl, wherein the alkyl group has 1 to 3 carbon atoms, β-hydroxyethyl, 2-(1,3-dioxolan-2-yl)-ethyl, 2-(1,3-dioxan-2-yl)-ethyl, 3,4-methylene-dioxy-benzyl, pyrrolidinocarbonylmethyl, phenyl, phenyl substituted by methoxy, chloro, nitro or amino; allyl, propargyl, 3,4,5-trimethoxy-benzoyl, 3,4-methylenedioxy-benzoyl, 2-furoyl, 2-thenoyl, alkoxycarbonyl of 1 to 5 carbon atoms, in which the alkyl group of the latter may be substituted by the hydroxy group, or wherein R¹0 is hydrogen, and R¹1 a cyclohexyl group which is substituted by a dialkylamino group wherein each alkyl has 1 to 3 carbon atoms,

or R² is a group of the formula ##STR12## wherein A¹ stands for a straight-chained or branched alkylene group of 2 or 3 carbon atoms, which may be substituted by a hydroxy group, and R¹2 and R¹3 stand for straight-chained or branched alkyl groups of 1 to 3 carbon atoms, or R¹2 and R¹3 together with the nitrogen atom form a 5- or 6-membered ring which may contain a hetero atom, especially the piperidino, pyrrolidino, morpholino, 4-methyl-piperazino group;

furthermore, R² stands for an aminoalkyl group of the formula ##STR13## wherein A² stands for a straight-chained alkylene group of 2 or 3 carbon atoms, and R¹4 and R¹5 are different, R¹4 standing for hydrogen and R¹5 for a straight-chained or branched alkyl group of 1 to 4 carbon atoms or a cyclohexyl group, or R¹4 and R¹5 are identical and stand for alkyl group of 1 to 4 carbon atoms, or together with the nitrogen atom they form a 5- or 6-membered ring which may contain a hetero atom, especially the morpholino, 4-methylpiperazino, piperidino and pyrrolidino groups;

for R³ : hydrogen, alkoxy groups of 1 to 4 carbon atoms, especially the methoxy group, preferably in 4-, 5- and/or 6-positions;

for R⁴ : hydrogen, the methyl, phenyl, benzyl group, or a o-, m- or p-alkoxyphenylgroup, wherein the alkoxy group has 1 to 4 carbon atoms, especially the methoxy-phenylgroup.

Further object of this invention is a process for the manufacture of the compounds of formula I, which comprises

(a) reacting a compound of the formula II ##STR14## in which R stands for a chlorine or bromine atom, R² stands for a hydrogen atom, an alkyl or phenyl group, and R³, R⁴ and m are defined as in formula I, with an amine of the formula ##STR15## wherein R⁵ and R⁶ are defined as in formula I, or

(b) reacting an indole 3-carboxylic acid of the formula III ##STR16## in which R¹, R³, R⁴ and m are defined as above, with an amine of the formula ##STR17## or with an alcohol of the formula ##STR18## or HO--(CH₂)_n --R¹6, wherein A², R¹0, R¹1, R¹4, R¹5 and R¹6 are defined as in formula I and n is an integer of 0 or 1, or

(c) reacting a compound of the formula IV ##STR19## in which R stands for a chlorine or bromine atom, R³, R⁴ and m are defined as in formula I, and R² stands for an amino group of the formula ##STR20## or an aminoalkyloxy group of the formula ##STR21## or a hydroxy group of the formula HO-(CH₂)_n -R, in which A², R¹0, R¹1, R¹4, R¹5, R¹6 and n are defined as in formula I, with an amine of the formula ##STR22## wherein R⁵ and R⁶ are defined as in formula I, or

(d) reacting a compound of the formula V ##STR23## in which R¹ to R⁴ and m are defined as in formula I, with the proviso that one or the two radicals R¹ and R² contain a secondary amino group, with an alkylating agent of the formula XR¹7, in which X stands for a chlorine or bromine atom and R¹7 for a straight-chained or branched alkyl group of 1 to 6 carbon atoms, which may be substituted by hydroxy, alkoxy of 1 to 4 carbon atoms, dialkylamino of 1 to 4 carbon atoms, ethylene-dioxy, trimethylene-dioxy, or the group ##STR24## wherein R⁷ and R⁸ are defined as in formula I, or by an optionally substituted phenyl group, or for alkenyl or alkinyl of 3 to 8 carbon atoms each, or with a chloroformiate of the formula ClCOO--(C₁ -C₄)--alkyl, in which the alkyl groups carry hydroxy or alkoxy groups of 1 to 4 carbon atoms, or of the formula ClCOO--(C₃ -C₆)--alkenyl, or with a compound of the formula ClCOR⁹, wherein R⁹ is defined as in formula I, or

(e) converting a compound of the formula VI ##STR25## in which R¹, R³, R⁴ and m are defined as in formula I, into a compound of formula I either by reaction with phosphorus oxychloride/N,N'-dimethylformamide, if R² in formula I is hydrogen, or by reaction with an aliphatic or aromatic acid chloride, if R² in formula I is alkyl or phenyl, or by reaction with a chloroformic acid methyl or ethyl ester, if R² in formula I is methoxy or ethoxy, or

(f) reacting a compound of the formula VII ##STR26## in which R², R³, R⁴ and m are defined as in formula I, and R¹8 stands for an alkyl group of 1 to 4 carbon atoms or the phenyl group, with an amine of the formula ##STR27## wherein R⁵ and R⁶ are defined as above.

According to method step (a), at least twice the equivalent amount of amine is added, since one mol of amine is required to bind the hydrogen halide that has been split off; but in some cases, it is advantageous to use an up to 15-fold excess of amine to accelerate the reaction. As solvents, there are mentioned, inasfar as they are used for the reaction, inert anhydrous organic solvents, such as dioxan, 1,2-dimethoxy-ethane, diethylene-glycol dimethyl ether, diethylene-glycol dibutyl ether, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, trichlorobenzene, N,N'-dimethylformamide, dimethylsulfoxide or hexamethyl-phosphoric acid triamide. The reaction is generally carried out at temperatures of from 50° to 220°C, preferably from 80° to 180°C

According to method step (b), the carboxylic acids of formula III are converted according to the usual method of ester or amide formation, for example via the acid chlorides or the mixed anhydrides, into the esters or amides. For the esterification with alcohols which still contain secondary amino groups, the salts of the amino alcohols are used.

For the method step (c), the test conditions disclosed for method (a) are applicable.

According to method step (d), the secondary amino groups are reacted according to known methods; for example, formylation is performed by heating with formiates, acylation by reaction with acid chlorides and alkylation with haloalkyl compounds.

According to method step (e), the compounds of formula VI are reacted according to known methods (e.g. A. Deberly and J. Bourdais, Tetrahedron Letters 1971, p. 3049) with acid chlorides, chloroformiates or with dimethylformamide/phosphorus oxychloride.

According to method step (f), the principle of method (a) is followed but, in most cases, higher temperatures are required for the exchange of the alkoxy group as compared to the halogen atom.

The starting compounds for methods (a) to (e) may be prepared as disclosed in copending patent application Ser. No. 751,090 filed Dec. 16, 1976, now abandoned.

According to this patent application, for example, an optionally substituted oxindole is reacted with phosphoroxychloride or -bromide and dimethylformamide in a solvent, for example, toluene, at a temperature of about 30°C to give the corresponding 2-chloro-(or-bromo)-indol-3-carboxaldehyde. The aldehyde so obtained is then oxidized according to the usual methods, for example potassium permanganate, to give the corresponding carboxylic acid, which can then be converted, according to the usual methods of the ester or amide formation, for example, via an acid chloride or a mixed anhydride, into an ester or an amide. The esterification with alcohols, which additionally contain secondary amino groups, is carried out using the salts of the amino alcohols. The compounds obtained according to the last-mentioned method, can be further alkylated with the usual alkylation agents on the secondary amino group.

The compounds of the invention have valuable therapeutic properties. For example, in addition to other pharmacological properties, they have an effect on the cardiac circulation that appears in a hypotensive effect and especially in an antiarrhythmic activity. Therefore, these compounds are suitable for the treatment of disturbances in the cardiac rhythm. This antiarrhythmic activity was established on dogs that had been poisoned with strophanthin, on cats that had been exposed to hypothermia and by means of the digitoxin-aconitin fibrillation test on the guinea pig-Langendorff heart.

The novel compounds may be used alone or in admixture with pharmacologically acceptable carrier material. For oral administration the active compounds are mixed with the usual substances and brought into the usual dosage unit forms by known methods, for example tablets, gelatin capsules, aqueous, alcoholic or oily suspensions or aqueous, alcoholic or oily solutions. As inert carrier material, there may be used, for example, magnesium carbonate, lactose or corn starch, in conjunction with other substances, for example magnesium stearate. The composition may be in the form of dry or moist granules. Vegetable and animal oils, for example sunflower oil or castor oil are especially useful as oily carrier materials or solvents.

Especially advantageous is the intravenous administration. For this purpose, the active compounds or the physiologically acceptable salts thereof are dissolved together with the usual substances. Such physiologically acceptable salts are formed with the following acids, for example: hydrochloric acid, hydrobromic acid or hydroiodic acid, phosphoric acid, sulfuric acid, methyl-sulfuric acid, amidosulfonic acid, nitric acid; formic acid, acetic acid, propionic acid, succinic acid, tartaric acid, lactic acid, malonic acid, fumaric acid, oxalic acid, citric acid, malic acid, mucic acid, benzoic acid, salicylic acid, aceturic acid, embonic acid, naphthalene-1,5-disulfonic acid, ascorbic acid, phenylacetic acid, p-aminosalicyclic acid, hydroxyethane-sulfonic acid, benzene-sulfonic acid, or synthetic resins containing acid groups, for example those having an ion exchanger effect.

As solvents of the corresponding physiologically acceptable salts of the active compounds suitable for intravenous administration, there are mentioned, for example, water, a physiological sodium chloride solution or alcohols, for example ethanol, propane-diol or glycerol; furthermore, sugar solutions, for example glucose or mannitol solutions, or mixtures of the various solvents mentioned.

For oral administration, the single dose is within the range of from 50-1,000 mg, preferably from 100-500 mg, for the intravenous or intramuscular administration, it is within the range of from 20-100 mg, preferably 50 mg.

The daily dose in each case is for the oral administration within the range of from 50-2,000 mg, preferably 500 mg, for the intravenous or intramuscular administration within the range of from 20-500 mg, preferably 100 mg. The pharmacological effect has been tested on rats.

The following Examples illustrate the invention.

EXAMPLE 1

PAC 1-Phenyl-2-piperazino-3-indole carbaldehyde

A mixture of 51.2 g (0.2 mol) of 2-chloro-1-phenyl-3-indole carbaldehyde and 172 g (2 mols) of anhydrous piperazine in 500 ml of dioxan free of peroxides was refluxed for 22 hours. After cooling, the mixture was diluted with 1.5 l of water, the crystal mass that had separated was suction-filtered after standing overnight and washed with water. After drying, the product was recrystallized from ethyl acetate.

Yield: 46 g (75% of the theoretical yield) of yellowish crystals which melted at 176-178°C; the hydrochloride melted at 260°C

The 2-substituted indole 3-aldehyde derivatives of the Examples listed in Table 1 were prepared as above from 2-chloro-indole 3-carbaldehyde and the corresponding bases.

TABLE 1
__________________________________________________________________________
##STR28##
Example
R1       R3
R4   m.p. °C, salt (m.p. °
C.)
__________________________________________________________________________
##STR29##    H    C6 H5
180°; hydrochloride (240°-
242°)
3
##STR30##    H    C6 H5
resin; hydrochloride (214°-
216°)
4
##STR31##    H    C6 H5
167°- 168°
5
##STR32##    H    m-CH3 OC6 H4
amorphous; hydro- chloride (230°-
232°)
6
##STR33##    5-CH3 O
CH3  amorphous; hydro-  chloride (decomp.
>250°)
__________________________________________________________________________

EXAMPLE 7

PAC 1-Phenyl-2-(1-piperazinyl)-indole 3-carboxylic acid (4-methyl)-Piperazide

106 g (0.3 mol) of 2-chloro-1-phenyl-indole 3-carboxylic acid (4 -methyl)-piperazide and 258 g (3 mols) of piperazine were refluxed for 17 hours in 1 l of diethylene-glycol dimethyl ether. After cooling, the mixture was diluted with water, extracted twice with methylene chloride and the solvent was eliminated in vacuo. The oily residue was dissolved in 300 ml of ethyl acetate while heating and allowed to stand overnight at +5°C The precipitate was suction-filtered and washed with ethyl acetate.

Yield: 111 g (91 % of the theoretical yield) of light-brown crystals, m.p. 201°-202°C; dihydrochloride decomposed above 280° C.

The substituted 1-phenyl-indole 3-carboxylic acid derivatives of formula I as listed in the Examples of Table 2 and the pharmacologically useful salts thereof were prepared according to Example 7 from the 2-chloro-1-phenyl-indole 3-carboxylic acid derivatives (R¹ = Cl) and the corresponding bases.

TABLE 2
__________________________________________________________________________
##STR34##
Example
R2         R1      melt.p. °C, salt (m.p.
°C)
__________________________________________________________________________
8   4-methyl-1-piperazinyl
4-methyl-1-piperazinyl
150°; Di-HCl (220°)
9   4-methyl-1-piperazinyl
morpholino   196°-197°; HCl
(255°)
10   4-methyl-1-piperazinyl
piperidino   165°-166°; HCl
(240°)
11   dimethylamino   4-methyl-1-piperazinyl
178°; HCl (230°)
12   dimethylamino   1-piperazinyl
211°; HCl (230°)
13   dimethylamino   4-phenyl-1-piperazinyl
166°
14   1-piperazinyl   1-piperazinyl
160°-163°; Di-HCl
(270°)
15   1-piperazinyl   morpholino   120°-123°; HCl
(270°-272°)
16   1-piperazinyl   piperidino   152°; HCl (215°)
17   4-phenyl-1-piperazinyl
1-piperazinyl
176°-178°; HCl
(210°)
18   4-phenyl-1-piperazinyl
4-methyl-1-piperazinyl
179°; HCl (200°)
19   4-phenyl-1-piperazinyl
piperidino   206°; HCl (190°)
20   4-phenyl-1-piperazinyl
morpholino   201°-203°; HCl
(190°)
21   4-hydroxyethyl-1-piperazinyl
1-piperazinyl
144°-146°; Di-HCl
(240°)
22   4-hydroxyethyl-1-piperazinyl
4-methyl-1-piperazinyl
130°-131°; Di-HCl
(210°)
23   4-hydroxyethyl-1-piperazinyl
morpholino   134°-135°; HCl
(220°)
24   piperidino      1-piperazinyl
190°; HCl (290°-291.degree
.)
25   piperidino      4-methyl-1-piperazinyl
151°; HCl (278°)
26   morpholino      1-piperazinyl
Harz; HCl (246°)
27   morpholino      4-methyl-1-piperazinyl
169°-170°; HCl
(280°)
28   pyrrolidino     1-piperazinyl
Harz; HCl (Zers. >300°)
29   pyrrolidino     4-methyl-1-piperazinyl
Harz; HCl (265°)
30
##STR35##      1-piperazinyl
172°-173°; Di-HCl
(250°)
31
##STR36##      4-methyl-1-piperazinyl
156°-157°; Di-HCl
(190°)
32   NHCH2 CH(OH)CH2 N(C2 H5)2
1-piperazinyl
129°; Di-HCl (210°)
33
##STR37##      1-piperazinyl
187°; HCl (190°-193.degree
.)
34
##STR38##      4-methyl-1-piperazinyl
192°; HCl (176°-178.degree
. )
35   4-Methyl-1-piperazinyl
3-methyl-1-piperazinyl
107°; Di-HCl (decomp.
>310°)
36
##STR39##      1-piperazinyl
56°-58°; Di-HCl;
>280°
37
##STR40##      morpholino   amorphous; hydrochloride, decomp.
>230°
38
##STR41##      1-piperazinyl
194°; Di-HCl ;
decomp. >260°
39
##STR42##      4-methyl-1-piperazinyl
192°; Di-HCl ;
decomp.  270°
__________________________________________________________________________

EXAMPLE 40

PAC 2-(4-Methyl-1-piperazinyl)-1phenyl-indole 3-carboxylic acid (4-hydroxy) piperidine

To a solution that had been cooled to -20°C and which consisted of 14.5 g (0.05 mol) of 2-chloro-1-phenyl-indole 3carboxylic acid chloride in 30 ml of chloroform, a mixture of 6 g (0.06 mol) of 4-hydroxy-piperidine, 8 ml of pyridine and 10 ml of chloroform was added. The mixture was allowed to stand for 2 hours at room temperature and then washed with dilute hydrochloric acid and with water. The resinous residue of the organic phase was chromatographed using silica gel 60 (0.06-0.2 mm, deactivated by 10% of water, column size: 4 × 110 cm) with chloroform containing 5% methanol. After elution of 1.3 l, the 2-chloro-1-phenyl-indole 3-carboxylic acid (4-hydroxy)-piperidine was eluted as a resin. The yield was 12 g (68% of the theoretical yield). A mixture of 5.3 g (15 mmols) of this resin, 15 g of N-metyhl-piperazine and 50 ml of diglym was heated to the boil for 24 hours, the cooled mixture was then worked up as in Example 7. The crystallized residue of the organic phase was digested with ether to yield 5 g (80%) of the product, m.p. 195°C; the hydrochloride melted at 160°-165° C.

EXAMPLE 41

The following substituted 1-phenyl-indole 3-carboxylic acid derivatives of formula I listed in Table 3 were prepared according to Example 7 and Example 40 from 2-chloro-1phenyl-indole 3-carboxylic acid derivatives of formula I (R¹ = Cl) and the corresponding amines.

TABLE 3
______________________________________
##STR43##
R2               R1
______________________________________
3-hydroxymethylpiperidino
1-piperazinyl
4-hydroxy-piperidino  1-piperazinyl
4-ethoxycarbonyl-piperidino
1-piperazinyl
3-methyl-piperidino   1-piperazinyl
3,5-dimethylmorpholino
1-piperazinyl
4-phenylpiperidino    1-piperazinyl
hexamethylenimino     1-piperazinyl
heptamethylenimino    1-piperazinyl
NHCH2 CH2 OCH3
4-methyl-1-piperazinyl
N(CH3)CH2 CH2 OH
4-methyl-1-piperazinyl
NHCH2 CH(OH)CH2 Cl
4-methyl-1-piperazinyl
NH(CH2)3 COOH
4-methyl-1-piperazinyl
NHCH2 CH2 NHCOCH3
4-methyl-1-piperazinyl
NHCH2 CH(OH)CH2 OCH2 CHCH2
4-methyl-1-piperazinyl
4-methyl-1-piperazinyl
NHC(C2 H5)2 CCH
4-methyl-1-piperazinyl
NHC(CH3)2 CH2 CH3
4-methyl-1-piperazinyl
##STR44##            4-methyl-1-piperazinyl
NHCH2 CH2 CH(C6 H5)2
4-methyl-1-piperazinyl
##STR45##            4-methyl-1-piperazinyl
NHCH2 CH2 N(C2 H5)2
4-hydroxy-piperidino
NHCH 2 CH2 N(C6 H5)2
4-ethoxycarbonyl-
piperidino
##STR46##            morpholino
##STR47##            morpholino
##STR48##            morpholino
##STR49##            1-piperazinyl
##STR50##            1-piperazinyl
##STR51##            1-piperazinyl
##STR52##            4-methyl-1-piperazinyl
##STR53##            4-methyl-1-piperazinyl
##STR54##            4-methyl-1-piperazinyl
______________________________________

EXAMPLE 42

PAC 1-(3-Methoxy phenyl)-2-(1-piperazinyl)-indole 3-carboxylic acid (4-methyl)-piperazide

To a solution of 3.2 g (10 mmols) of 2-chloro-1-(3-methoxyphenyl)-indole 3-carboxylic acid chloride in 20 ml of chloroform, a mixture pf 2.2 ml of N-methyl-piperazine, 2.4 ml of pyridine and 5 ml of chloroform was added while cooling. After standing for 1 hour at room temperature, the mixture was washed twice with water, and the solvent was evaporated in vacuo. The resinous residue, which was uniform according to thin-layer chromatography and consisted of 2-chloro-1-(3-methoxyphenyl)-indole 3-carboxylic acid (4-methyl)-piperazide, was dissolved in 40 ml of diglym, and after addition of 13 g (0.15 mol) of piperazine, the solution was heated to the boil. The cooled solution was diluted with methylene chloride, washed three times with water, and the solvent was eliminated in vacuo. The resinous residue was dissolved in chloroform, and an excess of ethanolic hydrochloric acid was added. The solvent was eliminated in vacuo, the crystallized residue was digested with acetone, suction-filtered and washed with acetone. The yield of faintly grey-colored dihydrochloride of the above compound amounted to 3.7 g (73% of the theoretical yield), m.p. 228°-230°C

EXAMPLE 43

PAC 1-(3-Methoxyphenyl)-2-(4-methyl-1-piperazinyl)-indole 3-carboxylic acid morpholide

This compound was prepared from 2-chloro-1(3-methoxyphenyl)-indole-3-carboxylic acid chloride and morpholine to yield 2-chloro-1-(3-methoxyphenyl)-indole 3-carboxylic acid morpholide which was reacted with N-methyl-piperazine according to Example 42. The yield of amorphous product was 85% of the theoretical yield; the amorpheus hydrochloride had a decomposition point above 160°C

EXAMPLE 44

Starting from 2-chloro-1-(3-methoxyphenyl)-indole 3-carboxylic acid chloride, the substituted 1-(3-methoxyphenyl)-indole 3-carboxylic acid derivatives of formula I and the pharmacologically useful salts thereof were prepared via the 2-chloro-1-(3-methoxyphenyl)-indole 3-carboxylic acid derivatives of formula I by reaction with the corresponding bases according to Examples 42, 40 and 7. The radicals R¹ and R² are listed in Tables 2 and 3 ##STR55##

EXAMPLE 45

PAC 5-Methoxy-1-methyl-2-(1-piperazinyl)-indole 3-carboxylic acid (4-methyl)-piperazide

In a manner analogous to Example 42, 2-chloro-5-methoxy-1-methyl-indole 3-carboxylic acid chloride was first converted into 4-methyl-piperazide, m.p. 124°-125°C, which reacted with piperazine in boiling diglym to yield the above compound, m.p. 151°-152°C; the dihydrochloride had a melting point of 230°-232°C The yield was 87% of the theoretical yield.

EXAMPLE 46

Starting from 2-chloro-5-methoxy-1-methyl-indole 3-carboxylic acid chloride, the substituted 5-methoxy-1-methyl-indole 3-carboxylic acid derivatives of formula I and the pharmacologically useful salts thereof were prepared via 2-chloro-5-methoxy-1-methyl-indole 3-carboxylic acid derivatives of formula I by reaction with the corresponding bases according to Examples 45, 42, 40 and 7. The radicals R¹ and R² are listed in Tables 2 and 3 ##STR56##

EXAMPLE 47

The following substituted indole 3-carboxylic acid derivatives of formula I listed in Table 4 were prepared according to Examples 7, 40, 42 and 45 from the 2-chloro-indole 3-carboxylic acid chlorides via the 2-chloro-indole 3-carboxylic acid derivatives of formula I by reaction with the amines of formula HR¹.

TABLE 4
__________________________________________________________________________
##STR57##
R1     R2        R3   R4
__________________________________________________________________________
4-methyl-1-piperazinyl
1-piperazinyl  4-Cl      H
4-methyl-1-piperazinyl
1-piperazinyl  5-Br      H
4-methyl-1-piperazinyl
4-hydroxyethyl-1-piperazinyl
7-Cl      H
1-piperazinyl
4-hydroxyethyl-1-piperazinyl
5-NO2
H
1-piperazinyl
4-hydroxyethyl-1-piperazinyl
5-NH2
H
1-piperazinyl
4-methyl-1-piperazinyl
5,7-DiBr  H
1-piperazinyl
4-methyl-1-piperazinyl
H         C6 H5 CH2
morpholino  4-methyl-1-piperazinyl
5-F       CH3
4-methyl-1-piperazinyl
4-methyl-1-piperazinyl
5-F       C2 H5
4-methyl-1-piperazinyl
4-methyl-1-piperazinyl
5-Cl      n-C3 H7
4-methyl-1-piperazinyl
4-methyl-1-piperazinyl
5-Br      n-C4 H9
4-methyl-1-piperazinyl
morpholino     5-NO2
CH3
4-methyl-1-piperazinyl
morpholino     5-NH2
CH3
4-methyl-1-piperazinyl
morpholino     4-CH3 O
CH3
4-methyl-1-piperazinyl
morpholino     7-CH3 O
CH3
4-methyl-1-piperazinyl
piperidino     5-C2 H5 O
CH3
4-methyl-1-piperazinyl
piperidino     5-C3 H7 O
CH3
1-piperazinyl
piperidino     5-C4 H9 O
C6 H5
1-piperazinyl
piperidino     5-C5 H11 O
CH3
1-piperazinyl
pyrrolidino    6-C2 H5 O
C6 H5
1-piperazinyl
pyrrolidino    6-C3 H7 O
C6 H5
1-piperazinyl
pyrrolidino    6-C4 H9 O
CH3
1-piperazinyl
pyrrolidino    6-C6 H5 CH2 O
C6 H5
4-methyl-1-piperazinyl
4-methyl-1-piperazinyl
5,6-DiCH3 O
CH3
4-methyl-1-piperazinyl
4-methyl-1-piperazinyl
5,6-DiC2 H5 O
C6 H5
piperazinyl 4-methyl-1-piperazinyl
5-C2 H5 O,6-CH3 O
CH3
piperazinyl 4-methyl-1-piperazinyl
5,6-DiC3 H7 O
CH3
__________________________________________________________________________

example 48

PAC 2-(4-methyl)-1-piperazinyl-1-phenyl-indole 3-carboxylic acid-2-morpholino ethyl ester

11.5 g (0.03 mol) of 2-chloro-1-phenyl-indole 3-carboxylic acid 2-morpholino-ethyl ester (as in Example 8) and 30 g (0.3 mol) of N-methyl-piperazine in 90 ml of diethylene-glycol methyl ether were maintained at 125°C for 17 hours. After cooling, the mixture was diluted with water, extracted twice with methylene chloride, the organic phase was freed from the solvent in vacuo and the crude resinous base was purified by chromatography using silica gel 60 (0.06-0.2 mm, deactivated by 10% of water, column size: 3 × 130 cm) with chloroform containing 10% methanol. The above compound was eluted as a resin and converted with ethanolic hydrochloric acid into a colorless dihydrochloride having a melting point of 190 to 193°C The yield was 9 g (67% of the theoretical yield).

The substituted indole 3-carboxylic acid esters of formula I, listed in Table 5, were prepared according to Example 48 from the 2-chloro-1-phenyl-indole 3-carboxylic acid esters and the corresponding base.

TABLE 5
__________________________________________________________________________
##STR58##
Example                        m.p. °C, salt
No.    R2        R1  (m.p. °C)
__________________________________________________________________________
49
##STR59##
1-piperazinyl
resin, DiHCl (decomp. 190°)
50
##STR60##     4-methyl-1-pipera- zinyl
resin, Di (255°-256°)
51
##STR61##     1-piperazinyl
resin, DiHCl (283°)
52
##STR62##     morpholino
106°, HCl (260°)
__________________________________________________________________________

EXAMPLE 53

The following substituted indole 3-carboxylic acid esters of formula I listed in Table 6 were prepared according to Example 48 from 2-chloro-indole 3carboxylic acid esters of formula I and the corresponding bases.

TABLE 6
______________________________________
##STR63##                     I
R1  R2           R3    R4
______________________________________
1-piperazinyl
OCH2 CH2 N(C2 H5)2
H          C6 H5
1-piperazinyl
OCH2 CH2 N(CH3)2
6-CH3 O
C6 H5
1-piperazinyl
O(CH2)3 N(CH3)2
5-CH3 O
CH3
1-piperazinyl
##STR64##        5,6-Di-CH3 O
CH3
1-piperazinyl
##STR65##        7-CH3 O
CH3
1-piperazinyl
##STR66##        6-C3 H7 O
C6 H5
4-methyl-1-
OCH2 CH2 NHCH(CH3)2
6-C2 H5 O
C6 H5
piperazinyl
4-methyl-1- piperazinyl
##STR67##        6-C6 H5 CH2 O
C6 H5
4-methyl-1- piperazinyl
##STR68##        5-C6 H5 CH2 O
C6 H5
4-methyl-1- piperazinyl
##STR69##        5-C3 H7 O
CH3
morpholino
##STR70##        5-C5 H11 O
CH3
morpholino
##STR71##        H          C6 H5
piperidino
##STR72##        H          C6 H5
1-piperazinyl
##STR73##        H          C6 H5
______________________________________

example 54

PAC 2-[4-(2-(1,3-dioxolan-2-yl)-ethyl)-1-piperazinyl]-1-phenyl indole 3-carboxylic acid (4-methyl)-piperazide

A stirred mixture of 8 g (0.02 mol) of 1-phenyl-2-(1-piperazinyl)-indole 3-carboxylic acid (4-methyl)-piperazide, 9.45 g (0.07 mol) of 2-(2-chloroethyl)-1,3-dioxolane and 9.7 ml of triethylamine in 60 ml of toluene was maintained at the boil for 40 hours. After cooling, the mixture was diluted with 200 ml of chloroform, washed three times with water, and the solvent was eliminated in vacuo. The resinous residue of the organic phase was chromatographed using silica gel 60 (0.06-0.2 mm, deactivated by 10% of water, column size: 3 × 100 cm) with chloroform containing 10% methanol. The base was eluted as a resin. The yield amounted to 6.6 g (66% of the theoretical yield). The dihydrochloride melted at 215°-217°C

EXAMPLE 55

PAC 2-[4-(3,4-methylene-dioxy-benzyl)-1-piperazinyl]-1-phenyl-indole 3-carboxylic acid 4-methyl-piperazide

This compound was prepared from 1-phenyl-2-(1-piperazinyl)-indole 3-carboxylic acid 4-methyl-piperazide and piperonyl chloride in boiling toluene according to Example 54. The resinous base was converted into a colorless dihydrochloride which melted at 210°-212°C The yield was 52% of the theoretical yield.

EXAMPLE 56

The compounds listed in Table 7 were prepared from the 1-piperazinyl compounds of formula I and the corresponding alkyl halides according to Examples 54 and 55.

TABLE 7
______________________________________
##STR74##                     I
##STR75##
R            R2       R3    R4
______________________________________
##STR76##   morpholino    H          C6 H5
CH2 CCH 4-phenyl-1-pipera-
H          CH3
zinyl
CH2 CCCH3
piperidino    H          C2 H5
CH2 CHCH2
pyrrolidino   H          C6 H5
##STR77##   hexamethylenimino
6-CH3 O
C6 H5
##STR78##   piperidinoamino
5-CH3 O
CH3
CH2 C6 H5
4-methyl-1-pipera-
5,6-Di-CH3 O
CH3
zinyl
CH2 CONHCH3
4-methyl-1-pipera-
6-C2 H5 O
C6 H5
zinyl
CH2 CH2 N(C2 H5)2
4-methyl-1-pipera-
H          C6 H5
zinyl
______________________________________

EXAMPLE 57

The compounds of Examples 54, 55 and 56 were alternatively prepared by reaction of 2-chloro-indole 3-carboxylic acid derivatives of formula I with the corresponding alkylated piperazines according to Examples 7, 40, 42 and 45. ##STR79##

EXAMPLE 58

PAC 2-(4-methyl-1-piperazinyl)-1-phenyl-indole 3-carboxylic acid [4-(2-1, 3-dioxolan-2-yl)-ethyl]-piperazide

This compound was prepared from 2-(4-methyl-piperazinyl)-1-phenyl-indole 3-carboxylic acid piperazide and 2-(2-chloroethyl)-1,3-dioxolane according to Example 54; amorphous; dihydrochloride decomposed above 260°C

EXAMPLE 59

The compounds listed in Table 8 were prepared from the indole 3-carboxylic acid piperazides and the corresponding alkyl halides according to Example 54.

TABLE 8
______________________________________
##STR80##
##STR81##
R              R1      R3  R4
______________________________________
##STR82##     4-methyl-1- piperazinyl
H        C6 H5
##STR83##     morpholino   H        CH3
CH2 CCH   piperidino   6-CH3 O
C6 H5
##STR84##     4-(2-hydroxy-  ethyl)-1-
5-CH3 O
CH3
piperazinyl
##STR85##     hexamethylen- imino
6-C2 H5 0
C6 H5
CH2 CH2 N(C2 H5)2
morpholino   H        C6 H5
______________________________________

example 60

PAC 2-[4-(2-furoyl)-1-piperazinyl]-1-phenyl-indole 3-carboxylic acid 4-methyl-piperazide

To a mixture of 16.1 g (0.04 mol) of 1-phenyl-2-(1-piperazinyl)-indole 3-carboxylic acid 4-methyl piperazide (Example 7), 5 ml of pyridine and 40 ml of chloroform, that had been cooled to -20°C, a solution of 6.5 g (0.05 mol) of furan-2-yl carboxylic acid chloride in 80 ml of chloroform was added. The mixture was allowed to stand for 4 hours at room temperature, then 200 ml of chloroform were added and the mixture was washed four times with water. The solvent was eliminated in vacuo, the crystallized residue was digested with ether, suction-filtered and washed with ether. Yield: 19 g (95% of the theoretical yield), m.p. 180°-181°C; the hydrochloride decomposed above 300° C.

EXAMPLE 61

PAC 1-Phenyl-2-[4-(3,4,5-trimethoxy-benzoyl)-1-piperazinyl]-indole 3-carboxylic acid 4-methyl-piperazide

This compound was prepared from 2-chloro-1-phenyl-indole 3-carboxylic acid 4-methyl-piperazide and 3,4,5-trimethoxy benzoic acid piperazide in boiling diglym according to Examples 7, 40, 42 and 45. The yield of amorphous product amounted to 77% of the theoretical yield. The hydrochloride melted at 253°-255°C

EXAMPLE 62

PAC 2-(4-Ethylcarbonyl-1-piperazinyl)-1-phenyl-indole 3-carboxylic acid 4-methyl-piperazide

A mixture of 4 g (10 mmols) of 1 -phenyl-2-(1-piperazinyl)-indole 3-carboxylic acid 4-methyl-piperazide, 10 ml of ethyl chloroformiate and 40 ml of ethanol were heated at the boil for 24 hours. After cooling, the precipitate was suctionfiltered and washed with ethanol. The yield amount of 4.2 g in the form of hydrochloride that decomposed above 300°C

EXAMPLE 63

PAC 2-(4-Isobutoxycarbonyl-1-piperazinyl)-1-phenyl-indole 3-carboxylic acid 4-methyl-piperazide

This compound was prepared from 2-chloro-1-phenyl-indole 3-carboxylic acid 4-methyl-piperazide and 1-piperazino-carboxylic acid isobutyl ester in boiling diglym according to Example 7 or in ethanol as a solvent in an autoclave at 150°C After a reaction time of 24 hours, in this case, the solvent was eliminated, the residue was digested with water, and the undissolved product was recrystallized from ethyl acetate/diisopropyl ether. M.p. 132°-133°C; yield: 81% of the theoretical yield. The hydrochloride melted at 314°-316°C

EXAMPLE 64

The compounds listed in Table 9 were prepared according to Examples 60 and 62 from the corresponding 1-piperazinyl compounds of formula I or according to Examples 61 and 63 from the 2-chloro-indole 3carboxylic acid derivatives of formula I and the substituted piperazines.

TABLE 9
__________________________________________________________________________
##STR86##                             I
R                R2    R3
R4
__________________________________________________________________________
##STR87##        4-methyl-piperazinyl
6-CH3 O
C6 H5
##STR88##        4-methyl-piperazinyl
5-CH3 O
CH3
##STR89##        4-methyl-piperazinyl
5-CH3 O
C2 H5
##STR90##        morpholino  5,6-DiCH3 O
CH3
COOCH2CHCH2
NHCH2 CH2 N(C2 H5)2
6-C2 H5 O
C6 H5
##STR91##        4-methyl-piperazinyl
H       C6 H5
COOCH2 CCH   4-methyl-piperazinyl
H       C6 H5
COOCH2C(CH3)CH2
4-methyl-piperazinyl
6-C6 H5 CH2 O
C6 H5
__________________________________________________________________________

example 65

the substituted indole 3-carboxylic acid piperazides of formula I were prepared according to Examples 60, 61, 62, 63 and 64. Corresponding radicals R¹, R³ and R⁴ are listed in the Tables 8 and 9, the radicals R are given in Examples 60 to 64 and in Table 9. ##STR92##

EXAMPLE 66

PAC 1-Phenyl-2-(1-piperazinyl)-indole 3-carboxylic acid-[4-(3,4-methylene-dioxybenzyl)]-piperazide

4,74 g (10 mmols) of 2-chloro-1-phenyl-indole 3-carboxylic acid-[4-(3,4-methylenedioxybenzyl)] piperazide and 8.6 g (0.1 mol) of piperazine were heated under reflux during 20 hours in 25 ml of diglyme. The cold solution was worked up as described in Example 42. The crystalline residue of the organic phase was digested with diisopropyl ether, suctionfiltered and washed.

Melting point: 127°-129°C, yield: 72% of the theory. The dihydrochloride had a melting point of 241°C (decomposit.)

EXAMPLE 67

PAC 2-[4-(2-Methyl-2-propenyl)oxycarbonyl-1-piperazinyl]-1-phenylindole-3-carbo xylic acid-4-methyl-piperazide

Reaction in analogy to Example 60 from 1-phenyl-2-(1-piperazinyl)-indole-3-carboxylic acid-4-methyl-piperazide and chloroformic acid-2-methyl-2-propenyl ester. After working up with methylene chloride and heated sodium carbonate solution, the crystalline residue of the organic phase was triturated with ether, suction-filtered and washed with ether. Melting point: 141°-143°C, yield: 94% of the theory.

EXAMPLE 68

PAC 2-[4-(2-Hydroxy-2-methylpropyl)-oxycarbonyl-1-piperazinyl)]-1-pheny-indole- 3-carboxylic acid-4-methyl-piperazide

3 g of 2-[4-(2-methyl-2-propenyl)oxycarbonyl-1-piperazinyl]-1-phenyl-indole-3-car boxylic acid-4-methyl-piperazide were stirred in 30 ml of 50% aqueous sulfuric acid for 20 hours at room temperature. The mixture was worked up with ice, concentrated sodium hydroxide solution and methylene chloride, the crystalline residue of the organic phase was digested with diisopropyl ether.

Yield: 90% of colorless product, melting point: 165°-166°C The hydrochloride had a melting point of about 260°C (decomposition).

Claims

1. A compound of the formula ##STR93## or a physiologically acceptable salt thereof wherein R¹ is piperidino, morpholino, piperazino, or piperazino substituted in the 4-position by

(a) alkyl having 1 to 3 carbon atoms

(b) β-hydroxyethyl

(c) 2-(1,3-dioxolan-2-yl)-ethyl

(d) phenyl

(e) 3,4-methylene-dioxybenzyl

(f) 2-furoyl

(g) 3,4,5, -trimethoxybenzoyl

(h) alkoxycarbonyl having up to 5 carbon atoms

(i) (2-methyl-2-propenyl)-oxycarbonyl, or

(j) hydroxyalkyl oxycarbonyl having 2 to 5 carbon atoms;

R² is hydrogen, dialkylamino having identical alkyl groups each having 1 to 4 carbon atoms, piperazino substituted in the 4-position by

(a) alkyl having 1 to 3 carbon atoms

(b) β-hydroxyethyl

(c) 2-(1,3-dioxolan-2-yl)-ethyl

(d) phenyl, or

(e) 3,4-methylene-dioxy-benzyl, or

R² is pyrrolidino, piperidino, 4hydroxy-piperidino, morpholino piperazino, [N-(1-ethinyl-cyclohexyl)]-amino, [N-(4-methylpiperazino)]-amino, [N-(dialkylaminocyclohexyl]-amino wherein each alkyl has 1 to 3 carbon atoms, ##STR94## wherein A¹ is alkylene having 2 or 3 carbon atoms or such alkylene mono-substituted by hydroxy and R¹2 and R¹3, taken alone, are each alkyl having 1 to 3 carbon atoms, or, taken together with the nitrogen atom to which they are attached, are morpholino,

or R² is ##STR95## where A² is straight-chain alkylene having 2 or 3 carbon atoms and R¹4 and R¹5 taken alone, are respectively hydrogen and cyclohexyl, or, taken together with the nitrogen atom to which they are attached, are morpholino;

R³ is hydrogen or methoxy; and

R⁴ is methyl, phenyl, or methoxyphenyl.

2. A compound or salt as in claim 1 wherein R¹ is piperazino or piperazino substituted in the 4-position by alkyl having 1 to 3 carbon atoms and

R² is piperidino, morpholino, piperazino, piperazino substituted in the 4-position by alkyl having 1 to 3 carbon atoms, or ##STR96##

3. The compound defined in claim 1 which is 1-phenyl-2-(1-piperazinyl)-indole 3-carboxylic acid (4-methyl)-piperazide.

4. The compound defined in claim 1 which is 1-phenyl-2-(1-piperazinyl)-indole 3-carboxylic acid piperazide.

5. The compound defined in claim 1 which is 2-[4-(2-(1,3-dioxolan-2-yl)-ethyl)-1-piperazinyl]-1-phenyl-indole 3-carboxylic acid (4-methyl)-piperazide.

6. The compound defined in claim 1 which is 1-phenyl-2-(1-piperazinyl)-indole 3-carboxylic acid-[4-(3,4-methylene-dioxybenzyl)]-piperazide.

7. A pharmaceutical composition for treating arrhythmia or hypertension, which composition comprises an effective amount of a compound or salt as in claim 1 and a pharmaceutical carrier.

8. A method for treating arrhythmia or hypertension in a patent suffering therefrom, which method comprises administering to said patient an effective amount of a compound or salt as in claim 1.